The present invention relates to a socket for an electrical part used for carrying out an electrical test of electrical parts such as electronic circuit board such as IC package and to parts or assembly constituting such socket.
For example, in a case where a burn-in test of an IC package (electrical part) such as BGA or LGA, the IC package is accommodated in a socket for electrical parts provided with contact pins formed of electrically conductive metal, and terminals formed to the lower surface of the IC package in shape of matrix are contacted to the contact pins to thereby establish an electrical connection, through the contact pins, between the terminals of the IC package and an external test circuit means.
Recent technology has provided the following technical ideas as prior art.
[First Prior Art]
Recently, in an IC package such as BGA or LGA, there is a requirement of realizing a small or compact structure of the IC package, and for this reason, contact pins having various shapes have been provided. For instance, one example is shown in FIG. 15, in which a contact pin 70 comprises a tubular (cylindrical) member 71 formed of an electrically conductive metal, a rod-shape contact (contact piece) 72 which is formed of an electrically conductive metal and disposed inside the tubular member 71 to be vertically movable, and a spring 73 by which the contact 72 is urged upward so as to contact the contact 72 to a terminal 8 of an IC package 10 so that the terminal 8 of the IC package 10 contacts electrically to an external test circuit means, not shown, through the rod-shape contact 72 and the tubular member 71. The contact pins 70 each of such structure are mounted inside the socket (not shown) for electrical parts so as to accord in numbers with the terminals 8 of the IC package 10.
[Second Prior Art]
FIG. 16 also shows another example of a contact pin of conventional structure, and, the contact pin 75 is formed of an electrically conductive material in form of a coil spring, which has one end contacting a terminal 8 of an IC package 10 and the other end contacting an external test circuit means, not shown, so as to accommodate the contact pin 75 in the socket body in a manner opposing to the terminal 8 of the IC package 10.
However, the contact pin 70 of the first prior art has a complicated structure and, it is hence difficult to easily manufacture the same. Moreover, since the contact pin 70 is not easily manufactured, a price or selling cost of the contact pin as a product is made expensive. Accordingly, a socket for electrical parts provided with a number of such expensive contact pins are also made expensive.
On the other hand, the contact pin 75 has a simple structure in comparison with the first example, and hence, it is relatively easily manufactured with cheap cost of product. However, in this contact pin 75, as the electrically conductive material is formed in shape of spiral coil having a long length, a large resistance is provided, thus being defective.
Furthermore, in these first and second prior art examples (conventional contact pins 70 and 75), the contact pins 70 (75) must be mounted one by one to a contact pin accommodation portion of the socket body so as to be coincident with a number of terminals 8 of the IC package 10, requiring a troublesome mounting working, thus being not effective.
An object of the present invention is to substantially eliminate defects or drawbacks encountered in the prior art mentioned above and to provide a structural part or member for the socket for electrical parts and provide such socket capable of reducing assembling working or steps and manufacturing cost.
This and other objects of the present invention can be achieved by providing, in one aspect, a contact pin assembly for a socket for electrical parts comprising:
a plurality of contact pins provided for a socket body of a socket for electrical parts; and
a connection member connecting all the contact pins with a predetermined distance between adjacent ones,
the predetermined distance being made substantially equal to a distance between adjacent ones of terminals provided for an electrical part which is held in the socket body.
In a preferred example, each of the contact pins comprises a spring function portion having elasticity, a contact portion which is formed to a top end side of the spring function portion and contacts the terminal of the electrical part, a conductive portion extending from the spring function portion on the side opposite to the contact portion, and a connection leg portion further extending from the conductive portion, the conductive portions of the respective contact pins being connected together by the connection member.
The contact pins are arranged laterally symmetrically with respect to a center line of the contact pin arrangement and when the contact portions of the contact pins are contacted to the terminals and pressed thereby, the contact portions of the laterally arranged contact pins are displaced respectively to a center line side and a side opposite to the center line side.
In this aspect, there is further provided a method of manufacturing a contact pin assembly which comprises a plurality of contact pins and a connection member connecting all the contact pins, the manufacturing method comprising:
forming a plurality of contact pins and contact pin connection portions integrally from a conductive elastic plate member;
arranging and fixing the contact pins by using a connection member with a predetermined distance between adjacent ones; and
removing thereafter the contact pin connection portions from the respective contact pins.
According to this aspect, since a plurality of contact pins are arranged with a predetermined distance (interval) by the connection member, the workability at the time of assembling to the socket for electrical parts can be improved.
The connection of the conductive portion between the spring function portion and the connection leg portion through the connection member does not give an adverse affect on the elastic deformation of the spring function portion and the connection of the connection leg portion to the external test circuit means.
Furthermore, according to the symmetric arrangement of the contact pins, when the contact pin assembly is incorporated in the socket and the contact portions of the contact pins are pressed by the terminals, the contact portions, separated into lateral two portions, are displaced in opposing directions from the center line of the contact pin arrangement. Therefore, the electrical part is not moved in one direction and good wiping effect can be achieved between the terminals of the electrical part and the contact portions of the contact pins.
Furthermore, according to the contact pin assembly manufacturing method of the above aspect, a plurality of contact pins can be extremely easily and exactly connected with a predetermined distance by using the connection member.
In another aspect of the present invention, there is also provided a contact pin assembling structure for a socket for electrical parts comprising:
a plurality of contact pins provided for a socket body of a socket for electrical parts, each of the contact pins comprising a spring function portion having elasticity, a contact portion which is formed to a top end side of the spring function portion and contacts the terminal of the electrical part, a conductive portion extending from the spring function portion on the side opposite to the contact portion, and a connection leg portion further extending from the conductive portion, the conductive portions of the respective contact pins being connected together by the connection member;
a connection member connecting all the contact pins with a predetermined distance between adjacent ones, the predetermined distance being made substantially equal to a distance between adjacent ones of terminals provided for an electrical part which is held in the socket body; and
a contact pin holding member formed of an insulating resin material, the contact pin holding member holding and fixing together the conductive portion and the spring function portion and the conductive portion and the connection leg portion.
In this aspect, there is further provided a method of manufacturing a contact pin assembling structure defined above, wherein the conductive portion and the spring function portion of the contact pin and the conductive portion and the connection leg portion of the contact pin are fixed to the contact pin holding member formed of an insulating resin material and, thereafter, the connection member is removed from the conductive portions of the contact pins.
According to this aspect, the conductive portion and the spring function portion of the contact pin and the conductive portion and the connection leg portion of the contact pin are fixed to the contact pin holding member, respectively, so that the contact pins can be held with predetermined distance in a stable fashion without causing positional shifting of the contact pins.
In a further aspect of the present invention, there is also provided a socket for electrical parts in which a plurality of terminals provided for an electrical part are electrically connected to an external test circuit means through a plurality of contact pins arranged in accordance with the arrangement of the terminals, wherein a plurality of contact pin assembling structures each having the structure defined above are laminated in numbers corresponding to the number of rows of the terminals of the electrical part.
In a more specific mode in this aspect, there is provided a socket for electrical parts comprising:
a socket body formed of an insulating resin material;
a cover mounted to the socket body to be opened or closed;
a plurality of contact pin assembling structures mounted to the socket body; and
a floating plate elastically supported by the socket body through a spring, the floating plate having a terminal accommodation portion in which terminals of an electrical part is accommodated,
the plurality of contact pin assembling structures being laminated in numbers corresponding to the number of rows of the terminals of the electrical part, and
each of the contact pin assembling structure comprising: a plurality of contact pins provided for the socket body, each of the contact pins comprising a spring function portion having elasticity, a contact portion which is formed to a top end side of the spring function portion and contacts the terminal of the electrical part, a conductive portion extending from the spring function portion on the side opposite to the contact portion, and a connection leg portion further extending from the conductive portion, the conductive portions of the respective contact pins being connected together by the connection member; a connection member connecting all the contact pins with a predetermined distance between adjacent ones, the predetermined distance being made substantially equal to a distance between adjacent ones of terminals provided for an electrical part which is held in the socket body; and a contact pin holding member formed of an insulating resin material, the contact pin holding member holding and fixing together the conductive portion and the spring function portion and together the conductive portion and the connection leg portion.
According to this aspect, a socket for electrical parts having an improved structure and attaining a stable function can be provided by disposing a plurality of contact pin assembling structures in a laminated state.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.